Apparatus for well cleaning



Nov. 14, 1939. w. J. CRITES APPARATUS FOR WELL CLEANING Filed Jan. 21, 1957' [Ill INVEN TOR. WlLBUR J CRITES A TTORNEYS.

Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE- Phillips Petroleum Delaware Company, a corporation of Application January 21, 1937, Serial No. 121,688

6 Claims This invention relates to improvements in well cleaning.

More specifically the invention relates to an apparatus for cleaning out bottom holes in wells operating with pumps.

In oil well pump installations, the present practice is to attach a screen to and directly below the standing valve assembly which is located at the bottom of the accumulation chamber of the pump. The purpose ofthis screen is to keep out larger particles of earth debris which might clog the pump. When there is a cave-in or a gradual accumulation of earth debris in the bottom hole, oil cannot flow into the screen and the pump becomes inoperative. It is then necessary to clean out the bottom hole either by removal of the tubing, pump, and screen and subsequent bailing or by backwashing through the screen perforations. Since removal of the tubing, pump. and screen is an expensive operation, the preferred method is backwashing. In the present invention instead of attempting merely to clean out the perforations in the screen as previously done, a sufiicient quantity of water or other suitable liquid is forced into the bottom hole to dilute the debris therein to a flowing consistency which when admitted to the accumulation chamber through thestanding valve will be further diluted by liquid retained there for that purpose to a consistency produceable by the pump.

The apparatus of this invention is readily applicable to a gas-lift device of the type disclosed by Stephens et al. in Patent 2,142,482 issued January 3, 1939. It is to be understood however that the invention is also applicable to any well using a gas lift pump.

An important object of the invention is the provision of an apparatus for cleaning out the bottom hole in a well in an efficient manner.

A further object of the invention is the provision of a cleanout device for the bottom hole of a well which will not interfere with normal pumping operations.

A still further object of the invention is the provision of a cleanout device for the bottom hole of a well which forms part of the pump assembly.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawing, forming a part of this specification, and in which like numerals designate like parts throughout the same:

Fig. l is a view partly in elevation and partly in section of a device embodying the invention,

Fig. 2 is a cross-sectional view taken on the line 2-4 of Fig. l, I

Fig. 3 is a cross-sectional view taken on the line 3--3 of Fig; 1 and in which the valve springs have been omitted to simplify the showing,

Fig. 4 is a schematic showing of the device of Fig. 1 in position in a bottom hole, and

Fig. 5 is a view in longitudinal section of another embodiment of the lower section of the fitting.

In the drawing, wherein for the purposes of illustration, is shown a preferred embodiment of my invention, the numeral 6 designates generally a fitting formed for purposes of manufacture by an upper section 1 and a lower section 8. The sections meet at a ground joint 9 and are held together by cap screws I0 in recesses ll. Upper section 1 is internally screw threaded at l2 and lower section 8 has an annular bore l3, screw threaded on both its cylindrical walls at I and I5. Engaging threads I4 is a tube l6 terminating at its lower end in a standing valve l'l including valve seat 18 and a supporting element l9. Engaging threads I5 is a tubing 20 spaced from tubing [6 and terminating in a bull plug 2| having openings 22 forming a screen. Fitting 6 has passages 23 drilled through its side wall near the top closed by plugs 24. Each passage connects through a port 25 with a bore 26 extending downwardly through the wall to a point adjacent the upper end of annular bore I3 with which it is in communication by a port 21. In each bore 26 is a valve 28 closing port 25 by the action of a spring 29. Valve 28 is spaced from the walls of bore 26 by guides 30.

Fig. 4 shows the arrangement of the device in operating position. A casing is shown at 3| cemented at 32 to the bore hole wall in the neighborhood of the producing formation. A tubing string 33 is connected at its lower end to a gaslift pump 34 having a discharge tube 35 and a fluid pressure conduit 36 extending from its lower end. Discharge tube 35 extends upwardly through the pump to be connected to a flow string 31 which in turn continues upwardly to the surface of the ground. The space 38 between strings 33 and 31 is hermetically sealed above the ground and constitutes a fluid pressure conduit to the gas-lift pump 34 from a fluid pressure pipe 39 at the surface. ter 40 and a control valve M. It is apparent from an inspection of Fig. 4 that the device of the present invention constitutes a modified accumulation chamber for the gas-lift pump extending into bottom hole 42. A tube 43 depends from Pipe 39 includes an intermit-- the lower end of pump 34 and is screw threaded into threads l2 of the fitting-6. Thus tube 43,

fitting 6, tubes l6 and 20 with valve I1 and bull plug 2! form an accumulation chamber for pump 34 in which the lower part is formed of concentric, spaced receptacles, the inner one closed at the bottom by standing valve I1 and the outer one bybull plug 2| and the space in between these receptacles communicating with the interior of the accumulation chamber at fitting 6 when valves 28 are open.

In Fig. 5 a modification of fitting section I of Fig. 1 is shown wherein instead of being integral throughout, the section is shown formed of two telescoping machined cylinders 1A and l--.B which may be a more desirable construction for purposes of manufacture. In this form threads I4 and I5 are cut in cylinders 'IA and 1-3 respectively before they are assembled and to such a depth that on assembly an annu-' lar recess I3 is formed. A lip 'lC is formed on cylinder l-A to positively position the two cylinders with respect to one another.

As is well known to those skilled in the art, the gas-lift pump applies gas under pressure to the surface of the oilin the accumulation chamber forcing the oil up discharge tube 35 and flow string 31. Springs 29 are so designed that valves 28 are not opened by the usual operating pressures in the accumulation chamber. When the oil level in the accumulation chamber has been lowered to a point near the lower end of discharge tube 35, the gas pressure supplied to pump 34 through fluid conduit 31 is cut off by intermitter 40 and the pump operates to exhaust the gas under pressure from the accumulation chamber, allowing the oil in the bottom hole to flow into the accumulation chamber, filling i again for a succeeding pressure stage, initiated by the action of the intermitter in reinstatin the gas pressure. However, when rock and dirt debris accumulates in the bottom hole, either from natural disintegration of its walls or from a'cave-in thereof, the openings 22 in bull plug 2| become stopped preventing the oil inthe bottom than the usual pumping pressures is then applied to space 38, the same pressure being applied to flow string 31. The latter step prevents the pump from operating. It can readily be seen that all the liquid above passage 23 will be forced past valve 28, down through the conduit formed by bores 26 and the annular space between the inner and outer receptacles, to the openings in the bull plug and into thebottom hole 42. If desirable as in the case of cave-ins the application of high pressure gas can be continued to agitate the mixture of mud in the bottom hole. Upon relieving the pressure on space 38 and flow string 31, the gas in the accumulation chamber above port 23 will be exhausted by' the operation of the pump. The mud produced outside the bull plug will flow into the bull plug and up through the standing valve where it will be further diluted by the liquid remaining in the accumulation chamber below passa e 23. thus reducing its consistency to a point at which it can be more easily handled by the gas-lift pump. The amount of liquid required will differ with the amount and character of the material blocking flow of oil in the bottom hole. It should be a sufilcient quantity to achieve the degree of consistency of mud in the accumulation chamber mentioned above. It may be necessary to repeat the entire operation several times to restore full flow of the oil.

' It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangements of parts may be resorted to without departing from the spirit of my invention, or the scope of the appended claims. v

I claim:

1. In a device of the character described, an accumulation chamber, a discharge tube within said accumulation chamber, a pressure fluid conduit opening into the upper end of said accumulation chamber exterior ofsaid discharge tube,

said accumulation chamber having inner arid outer spaced walls forming its lower portion, said inner wall having an opening at its lower end closed by a standing valve, said outer wall extending below said standing valve, a passage connecting the space between said inner and outer walls with the interior of said accumulation chamber above .said standing valve and a spring operated valve for said passage.

2. In a device of the character described, an

accumulation chamber, a discharge tube extending downwardly into said accumulation chamber and a pressure fluid conduit opening into the upper end of said accumulation chamber in the space between said discharge tube and said accumulation chamber, said accumulation chamber being formed in two parts, a fitting joining said two parts, said lower part comprising inner .and outer spaced receptacles open adjacent the lower end, a standing valve closing the opening in said inner receptacle, said outer receptacle extending below said standing valve, a passage in said fitting connecting the interior of said accumulation chamber with the space between the inner and outer receptacles, a spring biased valve in said passage permitting fluid above a predetermined pressure to pass from the interior of said accumulation chamber to the space between the inner and outer receptacles.

3. In a bottom hole cleanout device, a housing forming an accumulation chamber, a standing alve adjacentthe lower end of said accumulation chamber, an annular space in the accumulation chamber housing connecting the interior of said accumulation chamber at apoint above-said standing valve with the exterior'of said accumulation chamber below said standing valve, a valve controlling the entrance to said annular space for permitting fluid above a predetermined pressure to pass from the interior of said accumulation chamber through said space.

4. In a bottom hole cleanout device adapted to be lowered to the producing formation, an accumulation chamber, a standing valve adjacent the lower end of said accumulation chamber, said accumulation chamber being' formed of spaced concentric tubular members having a space between the respective members, said space being connected to the interior of said accumulation chamber at a point above said standing valve with the space having 'an outlet to the formation below the standing valve, and a valve controlling the inlet to the space from the accumulation chamber for permitting fluid above a predetermined pressure to pass from the interior of said accumulation chamber through said space to be discharged below the standing valve into the formation.

5. In a-bottom hole cleanout device adapted to be lowered to the producing formation, an accumulation chamber comprising spaced concentric o tubular members connected at the top by a fitting member, a standing valve mounted on the bottom of the inner concentric member with a bull plug mounted on the bottom of the outer concentric member, a space between the concentric members having an opening in the fitting member which ;0 tween the accumulation chamber and the space for permitting fluid abbve a predetermined pressure to pass from the interior of said accumulation chamber through said space to be discharged below the standing valve into the bull plug from "I whence it passes into the formation.

6. In a bottom hole cleanout device adapted to be lowered to the producing formation, an accumulation chamber comprising spaced concentric tubular members connected at the top by a fitting member, a standing valve mounted on the bottom of the inner concentric member with a bull plug mounted on thebottom of the outer concentric member, a space between the concentric members having an opening in the fitting member which communicates with the interior of the accumulation chamber, said space discharging into the bull plug below the standing valve, and a valve means controlling the opening in the fitting between the accumulation chamber and the space, said valve being held in a closed position by a spring which is so tensioned as not to be compressed by the normal pressures in the accumulation chamber, but; for predetermined pressures will open to allow liquid under pressure to pass from the interior of said accumulation chamber through the said space to be discharged below the standing valve into the bull plug from whence it passes into the formation.

WILBUR J. cams. 

